Manufacture of leather cloth and similar coated fabrics



May 11, 1943. J. H MCGILL 2,319,074

MANUFACTURE OF LEATHER CLOTH AND S IMILAR COATED FABRICS Fi ld Aug. 5. 1941 INVENTOR.

ATTORNEY.'-

Patented May 11, 1943 UNITED STATE s PATENT "OFFICE MANUFACTURE OF LEATHER CLOTH AND SIMILAR COATED FABRICS John Heron McGill, Debdale Park, Manchester,

England, assignor. to Imperial Chemical Industries Limited, a corporation of Great Britain Application August 5, 1941, Serial No. 405,548 In Great Britain August 12, 1940,

7 Claims. (01. 111-73) obtained by heating ethyleneunder a pressure of not less than about 500 atmospheres, if desired in the presence of a-minute amount of oxygen.

'Polythenes have molecular weights as measured by'the Staudinger solution viscosity method ranging from 2,000 to 30,000 ormore. In the claims the term. polythene has this meaning. British specification 481,515 discloses methods whereby polythene may be halogenated and states that the products can be employed for coating or impregnating materials such as paper or fabric.

In the present invention there are employed halogenated derivatives of those polythenes that are solid at ordinary atmospheric temperatures and do not melt or soften appreciably at temperatures below 100 C., referred to hereinafter as solid polythenes. The properties of halogenated solid polythenes vary according to their halogen content, for example in the case of chlorinated polythenes those containing to 30% chlorine are soft and rubbery, those containing 3% to 40% chlorine are soft and tacky, those containing 40 to 55% chlorine are tough and those containing more than 55% chlorin are hard and glassy.

Films, coatings and the like made from halogenated solid polythenes have many valuable properties such as low infiammability and a high capacity for repeated flexure, but their resistance to scratching and to the effect of light is less than that of films, coatings and the like made from nitrocellulose; and their light stability, unlike that of similar products obtained from nitrocellulose. is not very materially improved by the inclusion of pigments.

I have found that while nitrocellulose coatings do not adhere to halogenated solid poly-' thenes we can produce leathercloth and similar coated fabrics combining many valuable properties of nitrocellulose coated fabrics and halogenated solid polythene coated fabrics, by applying to a textile or other fabric coated with a composition based on halogenated solid polythenes one or more cementing coats comprising a resin compatible with the halogenated polythene and with nitrocellulose. and thereafter applying one or more coats of pigmented nitrocellulose composition, if desired containing a non-solvent plasticiser.

In putting the invention into eiiect there may be employed as theresin in the cementing layer one or more polymerised acrylic acid esters or methacrylic acid esters or an interpolymer thereof. Polyvinyl esters of organic acids may also be employed. Softening agents for the resin 7 may beincluded in the cementing layer, which may conveniently be applied in the form of a .solution in a solvent for the resin or in the form of an aqueous emulsion. Examples of suitable resins for the cementing layer include polymerised methyl acrylate, polymerised 2-ethylhexyl methacrylate, polymerised ethoxy-ethyh methacrylate, polymerised methyl methacrylate, polyvinylphthalate, and an emulsion polymer- -ised mixture of methyl-methacrylate and 2- ethyl hexyl methacrylate.

As the extent of protection given to the halo-' genated polythene coat is dependent on the opacityof the pigmented nitrocellulose coat and the strength and the adhesion of the nitrocellu lose coat is adversely affected by a largeproportion of pigment it is advisable to use a pigment of the highest opacity possible particularly as we have found that the adhesion of .the two coats is not satisfactory if a thicker coat of nitrocellulose than one given by spreading 2 oz. per square yard is used. a

As the halogen content of the halogenated solid polythenes is increased the tendency is for the strength of the resulting coatings as indicated by the scrub test to increase, but also for their thermoplasticity to increase, which may give rise to certain difliculties ii leathercloth made from highly chlorinated solid polythenes is to be embossed. For this reason it is often very advantageous to employ a mixture of halogenated solid polythenes of difiering halogen content obtained by chlorinating the polythene to differing degrees of chlorination.

The halogenated solid polythene layer may be pigmented, for instance, if it is desired to obscure cellulose lacquer may be applied. Othcr meth- I ods than spreading are, however, applicable for the application of the halogenated polythene layer; for instance the halogenated poLvthene composition may be calender-ed on to the base cloth.

The invention is illustrated in the accompanying drawing in which I represents the base fabric, 2 the coat of halogenated polythene, and 0.

the pigmented nitrocellulose coat. The dark line separating layers 2 and 3 represents the thin cementing coat.

The invention is further-illustrated by the the parts are parts following example in which by weight:

Example According to this example genated polythenes is used.

The halogenated chlorination of a solid polythene. having amolecular weight between 12,000 and 15,000, in a a mhrture of carbon tetrachloride solution at 70' C. to 26%- and 48% chlorine content respectively. The coating composition made up as follows:

Chlorinated polythene of chlorine Chlorinated polythene of 46% chlorine contoni- Yellow ochr V Benzol.

Cotton sheeting having a reed and' pick of /50weighing 7 or. to the square yard is coated by spreading with 4 oz. (dry weight) per square yard of the above composition in severalsuccessive'spreads, each dried oi! before applying the next.

A single spread of the following'soluticn is then applied over .the halogenated polythene lam- I I Parts Methyl methacrylate 4 Dibutyl phthalate ..'..a...... 3 Solvent mixture ot-bensol and indds alcohol in the ratio :20 by vo1ume. 40

e, polythenes are made by Parts.

The resulting coated fabric has a greater strength, asshewn by the scrub -test than would be obtained from a fabric coated with a similar number of coats of similar weight based on nitrocellulose. On the other hand it has greater stability to ultraviolet light and a greater scratch hardnessthan a fabric coated with a similar number of coats of similar weight based on halogenated polythene. It may be embossed by the normal method used in the nitrocellulose leathercloth industry. The cotton sheeting used may be dyed to match the shade of the leathercloth pattern.

As many seemingly widely diiferent embodiments of the invention will be apparent without departing from the spirit and scope thereof, it must be understood that the invention is not limited-except as defined in the appended claims.

I claim: t l. A method of manufacturing coated fabrics which comprises applying to a fabric coated with a composition comprising halogenated solid polythenes at least one cementing coat comprising a resin compatible both with halogenated polythenes and with nitrocellulose, and thereafter applying at least coat of pigmented nitrocellulose composition.

- ,2. A method as claimed in claim 1 in which the cementing coat comprises a polymer of at least one ester or an acid of the formula I inwhichxisaradlcal of the group which consistsofOHaandHandltisaradicalofthegroup which consists of alkyl and aikoxy alkyl 8. A method as claimed in claim lin' which the cementing coat comprises a polymerised vinyl ester of an organic acid.

The nitrocellulose coating composition is made up as iollows:

Nitrocdlulose 2 Castor oh I 4. Zinc chromate 4 Solvent mixture of ethyl acetate and ind trial alcohol in the ratio 40:80 by volume..- 12

Thisis appliedby spreading about 1-15 os.

Parts" "4. Amethodasclaimedinciaim linwhlch' the cementing coat comprises a polymeric ester of methacrylic acid.

5. A method as claimed in claim 1 in which the cementing coat comprises an emulsion polymerised mixture of methyl methacrylate and Z-ethyl hexyl methacrylate.

8. A method as claimed in claim lein which the cementing coat comprises polymeris'ed methyl acrylatc.

(dry weight) 'per square yard to the cementing layer as required inknown mannerto give satisfactory cover.

I. A method as claimed in claim 1 in which the halogenated polythene coat comprising a mixture of halogenated polythenes of different halogen content.

- JOHN HERON McGlLL. 

